Extra Payment Calculator
See what paying extra does to any loan. Enter the balance, the rate and either the time left or the payment, then an extra amount every month, once, or once a year, and get the interest saved, the months saved and the new payoff date.
How to Use
- Enter what you still owe and the interest rate (APR).
- Choose whether you know the time left on the loan or the monthly payment, and enter that one. The calculator works out the other.
- Pick how the extra is paid: every month, once (a bonus or tax refund), or once a year, and enter the amount.
- Set the payment number it starts with (1 is your next payment) and, if you like, the month of your next payment.
- Read the interest saved, the time saved and the new payoff date, then compare other amounts in the table under the tool.
Enter a loan to compare extra amounts.
Enter a loan to see its schedule.
Worked Example
$200 a month on a mortgage. $300,000 at 6.5% with 30 years left: r = 6.5% ÷ 12 = 0.0054167 and n = 360, so the payment is $1,896.20 and the interest over the loan is $382,633.47. Paying $1,896.20 + $200 each month, the first payment is $1,625.00 of interest, $271.20 of scheduled principal and the $200 extra, leaving $299,528.80. Kept up, the balance reaches zero at payment 277 instead of 360, and the interest comes to $279,184.67. That is $103,448.79 saved and 6 years 11 months sooner, for $55,200 of extra payments.
A one-time payment, now or later. A $5,000 tax refund paid with the next payment on a $220,000 loan at 6% with 25 years left ($1,417.46 a month) saves $16,439.45 of interest and 15 payments. Held back and paid 10 years later, with payment 121, the same $5,000 saves only $6,982.80 and 8 payments, because it has 10 fewer years to save interest on.
The common mistake: counting the payments you skip as the saving. Finishing 83 payments early looks like 83 × $1,896.20 = $157,384.60 kept in your pocket. But you paid $55,200 more along the way, and the last payment is a part payment. The real saving is the fall in everything you pay, which is the same as the fall in interest: $103,448.79.
Show Work
Formulas
Why Early Payments Save So Much
A level-payment loan is front-loaded with interest. Each month’s interest is charged on the balance still owed, so in the first year of a 30-year mortgage at 6.5%, most of every payment is interest: the first $1,896.20 payment on $300,000 is $1,625.00 of interest and only $271.20 of principal. An extra dollar paid then skips 30 years of interest on itself, which is why the table under the tool shows bigger savings for money paid earlier.
Paying ahead used to be harder. Before the 1930s most American home loans were short, interest-only loans that ended in a large balloon payment. Fully amortizing 20- and 30-year loans with a level monthly payment spread after the Federal Housing Administration, created by the National Housing Act of 1934, began insuring them. In those loans every payment repays some principal, and any extra principal shortens the loan.
Some loans still charge for paying early. The Consumer Financial Protection Bureau explains that a mortgage prepayment penalty, where there is one, usually applies when the whole balance is paid off within the first three or five years, for example by selling or refinancing, and sometimes to a large lump sum; small extra principal payments are not normally penalised. Car, personal and business loans vary, so read your agreement before sending a large payment.
About This Tool
This calculator answers one question for any fixed-rate loan — a mortgage, car loan, student loan or personal loan: what does paying more than the minimum do? Give it the balance, the rate and either the time left or the monthly payment, choose an extra amount every month, once, or once a year, and it runs the loan month by month with and without the extra. You get the interest saved, the months saved, the new payoff date and how much extra you paid in all, plus a table of other amounts and the full schedule. For other loan questions, such as finding the payment, rate or term of a new loan, use the Loan Calculator.
It assumes the extra goes straight to principal and that the rate does not change; it does not include escrow, fees or prepayment penalties. Everything runs in your browser; nothing you enter is sent anywhere. Estimates for planning and education — not financial, tax or legal advice.
Related tools: Loan Calculator, Mortgage Payoff Calculator, and Debt Payoff Calculator.
Frequently Asked Questions
How much does paying $200 extra a month save on a mortgage?
On a $300,000 mortgage at 6.5% with 30 years left, the payment is $1,896.20. Adding $200 a month from the next payment cuts the loan from 360 payments to 277, so it ends 6 years 11 months early, and the interest falls from $382,633.47 to $279,184.67: a saving of $103,448.79 for $55,200 of extra payments. $100 a month saves $60,994.79 and 4 years; $500 a month saves $179,759.08 and 12 years 6 months.
Is an extra payment worth more early in the loan?
Yes, because it stops interest on that money for every month that is left. A one-time $5,000 with the next payment on a $220,000, 6%, 25-year loan saves $16,439.45 and 15 payments. The same $5,000 paid 10 years later, with payment 121, saves $6,982.80 and 8 payments. Starting $200 a month on the $300,000 mortgage five years late saves $66,943.94 instead of $103,448.79.
Is it better to pay extra every month or once a year?
The same money paid sooner saves a little more. On the $300,000, 6.5%, 30-year mortgage, $100 more every month saves $60,994.79 and 4 years. Paying $1,200 once a year with every 12th payment saves $58,599.36 and 3 years 11 months, and the same $1,200 paid at the start of each year saves $63,417.82 and 4 years 1 month. Pick the schedule you can keep up.
Does my monthly payment go down if I pay extra?
Not on a standard fixed-rate loan. The payment stays the same and the loan simply ends sooner, because each extra dollar comes off the balance and less interest builds on it. With $200 a month extra, the $300,000 mortgage still costs $1,896.20 a month but needs 277 payments instead of 360. Some lenders will recast the loan to lower the payment after a large lump sum; ask yours, as that is a separate request.
How do I make sure an extra payment goes to principal?
Tell your lender the extra is a principal-only payment, by the option on their website, a note with the payment or a separate payment, and check the next statement. Otherwise some servicers hold it as an early payment of next month instead. On an $18,000 car loan at 7.9% with a $440 payment, $50 a month applied to principal saves $366.06 of interest and 5 payments. Check the loan papers for any prepayment penalty first.
How do I use the Extra Payment Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
Common Use Cases
A mortgage
$200 more a month on a $300,000 mortgage at 6.5% with 30 years left saves $103,448.79 of interest and ends it 6 years 11 months early.
A car loan
On an $18,000 loan at 7.9% paid at $440 a month, rounding up to $490 saves $366.06 and 5 payments.
A tax refund or bonus
A one-time $5,000 on a $220,000, 6%, 25-year loan saves $16,439.45 of interest and 15 payments when paid now.
Student loans
$1,000 once a year on a $35,000 student loan at 5.5% over 10 years saves $2,272.91 and finishes it 2 years early.
A personal loan
Paying $400 instead of $300 a month on $12,000 at 11.5% clears it in 36 payments instead of 51 and saves $989.36.
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